Parse ext_mapping_idc from el_bit_depth_minus8

And write it back properly.

Fixes #263

dolby_vision/CHANGELOG.md

@@ -1,4 +1,7 @@
 ## Unreleased
+- Added support for parsing `ext_mapping_idc` in `RpuDataHeader`.
+  - `ext_mapping_idc_0_4` represents the 5 lowest bits, and `ext_mapping_idc_5_7` the 3 remaining bits.
+
 C API:
 - Added `dovi_parse_itu_t35_dovi_metadata_obu` function.
 

dolby_vision/src/rpu/rpu_data_header.rs

@@ -33,6 +33,13 @@ pub struct RpuDataHeader {
     // [8, 16]
     pub bl_bit_depth_minus8: u64,
     pub el_bit_depth_minus8: u64,
+
+    /// Extended base layer inverse mapping indicator
+    pub ext_mapping_idc_0_4: u8,
+    /// Reserved
+    pub ext_mapping_idc_5_7: u8,
+
+    // [8, 16]
     pub vdr_bit_depth_minus8: u64,
 
     pub spatial_resampling_filter_flag: bool,
@@ -80,7 +87,17 @@ impl RpuDataHeader {
 
             if header.rpu_format & 0x700 == 0 {
                 header.bl_bit_depth_minus8 = reader.get_ue()?;
-                header.el_bit_depth_minus8 = reader.get_ue()?;
+
+                let el_bit_depth_minus8 = reader.get_ue()?;
+                // 8 lowest bits
+                header.el_bit_depth_minus8 = el_bit_depth_minus8 & 0xFF;
+
+                // Next 8 bits
+                let ext_mapping_idc = (el_bit_depth_minus8 >> 8) as u8;
+                // Lowest 5 bits
+                header.ext_mapping_idc_0_4 = ext_mapping_idc & 0x1F;
+                header.ext_mapping_idc_5_7 = ext_mapping_idc >> 5;
+
                 header.vdr_bit_depth_minus8 = reader.get_ue()?;
                 header.spatial_resampling_filter_flag = reader.get()?;
                 header.reserved_zero_3bits = reader.get_n(3)?;
@@ -205,7 +222,12 @@ impl RpuDataHeader {
 
             if self.rpu_format & 0x700 == 0 {
                 writer.write_ue(&self.bl_bit_depth_minus8)?;
-                writer.write_ue(&self.el_bit_depth_minus8)?;
+
+                let ext_mapping_idc =
+                    ((self.ext_mapping_idc_5_7 << 5) | self.ext_mapping_idc_0_4) as u64;
+                let el_bit_depth_minus8 = (ext_mapping_idc << 8) | self.el_bit_depth_minus8;
+                writer.write_ue(&el_bit_depth_minus8)?;
+
                 writer.write_ue(&self.vdr_bit_depth_minus8)?;
                 writer.write(self.spatial_resampling_filter_flag)?;
                 writer.write_n(&self.reserved_zero_3bits, 3)?;

src/tests/rpu.rs

@@ -1122,3 +1122,15 @@ fn source_p5_to_p8_001_end_crc32() -> Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn profile20_apple() -> Result<()> {
+    let (original_data, dovi_rpu) =
+        _parse_file(PathBuf::from("./assets/tests/profile20_apple.bin"))?;
+    assert_eq!(dovi_rpu.dovi_profile, 5);
+    let parsed_data = dovi_rpu.write_hevc_unspec62_nalu()?;
+
+    assert_eq!(&original_data[4..], &parsed_data[2..]);
+
+    Ok(())
+}